One interesting idea in exercise and rehabilitation divides exercises into closed chain and open chain. Chains are links of body parts, such as foot, ankle, knee, and hip during walking. In a closed chain the end of the chain farthest from the body is fixed, such as a squat where your feet are fixed and the rest of the leg chain moves. In open chains the end is free, such as in a seated leg extension.
Dr. Frank B. Smoot, MA, DD One of the most famous and most revealing experiments in the history of psychological research involved the subject of learned helplessness. I don’t have the room here to tell you as much about it as I’d like to, but any Psychology 101